GRINDING FEEDS AND SPEEDS Machinery's Handbook, 31st Edition
1278
Calculation Procedure 1) Calculate V 1 U , V 10 U , V 100 U and SMRR 1 U , SMRR 10 U , SMRR 100 U for ECT = 0.00017 mm a) V 1 U = the user Taylor constant C U = V U 3 T U 0.26 = 1800 3 7 0.26 = 2985 m/min, and SMRR 1 U = 1000 3 2985 3 0.00017 = 507 mm 3 /mm width/min b) V 10 U = C U ÷ 10 0.26 = 2985 ÷ 10 0.26 = 1640 m/min, and SMRR 10 U = 1000 3 1640 3 0.00017 = 279 mm 3 /mm width/min c) V 100 U = C U ÷ 100 0.26 = 2985 ÷ 100 0.26 = 900 m/min, and SMRR 100 U = 1000 3 900 3 0.00017 = 153 mm 3 /mm width/min 2) For ECT = 0.00017 mm, calculate the ratio of user Taylor constant to standard Taylor constant from the tables = C U ÷ C ST = C U ÷ V 1 = 2985 ÷ 5290 = 0.564 (see Table 6 for the value of C ST = V 1 at ECT = 0.00017 mm). 3) For ECT = 0.00033, 0.00050, and 0.00075 mm calculate the user Taylor constants from C U = C ST 3 (the ratio calculated in step 2) = V 1 3 0.564 = V 1 U . Then, calculate V 10 U and V 100 U and SMRR 1 U , SMRR 10 U , SMRR 100 U using the method in items 1b) and 1c) above. a) For ECT = 0.00033 mm V 1 U = C U = 4690 3 0.564 = 2645 m/min V 10 U = C U ÷ 10 0.26 = 2645 ÷ 10 0.26 = 1455 m/min V 100 U = C U ÷ 100 0.26 = 2645 ÷ 100 0.26 = 800 m/min SMRR 1 U , SMRR 10 U , and SMRR 100 U = 876, 480, and 264 mm 3 /mm width/min b) For ECT = 0.00050 mm V 1 U = C U = 3590 3 0.564 = 2025 m/min V 10 U = C U ÷ 10 0.26 = 2025 ÷ 10 0.26 = 1110 m/min V 100 U = C U ÷ 100 0.26 = 2025 ÷ 100 0.26 = 610 m/min SMRR 1 U , SMRR 10 U , and SMRR 100 U = 1013, 555, and 305 mm 3 /mm width/min c) For ECT = 0.00075 mm V 1 U = C U = 2395 3 0.564 = 1350 m/min V 10 U = C U ÷ 10 0.26 = 1350 ÷ 10 0.26 = 740 m/min V 100 U = C U ÷ 100 0.26 = 1350 ÷ 100 0.26 = 405 m/min SMRR 1 U , SMRR 10 U , and SMRR 100 U = 1013, 555, and 305 mm 3 /mm width/min Thus, the wheel speed for any desired wheel-life at a given ECT can be calculated from V = C U ÷ T 0.26 . For example, at ECT = 0.00050 mm and desired tool life T = 9, V 9 = 2025 ÷ 9 0.26 = 1144 m/min. The corresponding specific metal removal rate is SMRR = 1000 3 1144 3 0.0005 = 572 mm 3 /mm width/min (0.886 in 3 /inch width/min). Table 11. User Calculated Data, Group 6 Material ECT = 0.00017 mm ECT = 0.00033 mm ECT = 0.00050 mm ECT = 0.00075 mm User Constant C U = 2985 User Constant C U = 2645 User Constant C U = 2025 User Constant C U = 1350 V T SMRR V T SMRR V T SMRR V T SMRR 100 900 153 800 264 610 305 405 305 10 1640 279 1455 480 1110 555 740 555 1 2985 507 2645 876 2025 1013 1350 1013
Copyright 2020, Industrial Press, Inc.
ebooks.industrialpress.com
Made with FlippingBook - Share PDF online